Bernie Sanders said in Denver on Sunday that he will win Colorado’s presidential primary on the strength of a movement focused on working people, and then make President Donald Trump a one-term president.

“Brothers and sisters, with your help, we are going to win here in Colorado, we are going to win the Democratic nomination, and we are going to defeat the most dangerous president in modern history,” Sanders told an estimated 12,000 people who filled a cavernous exhibit hall in the Colorado Convention Center.

The Vermont senator, who describes himself as a democratic socialist, is looking to wins in Colorado and other Super Tuesday states that vote on March 3 to solidify his status as the frontrunner in a crowded primary field.

The Sanders campaign on Thursday moved the rally to the exhibit halls from the convention center’s 5,000-seat Bellco Theater, citing demand for tickets.

Sanders spoke to thousands of supporters in the same location two years ago before winning Colorado’s caucuses by a 20-point margin over Hillary Clinton.

Interrupted frequently by thunderous cheers, Sanders on Sunday argued that Trump was a “fraud” who has made matters worse for working Americans.

“Our campaign is about a few fundamental issues, and at the top of the list is the need to defeat Donald Trump,” Sanders said. “We cannot continue to have president who is a pathological liar, who is running a corrupt administration, who has no clue what the Constitution of the United states is about, who is a bully, who is a racist, who is a sexist, who is a homophobe, who is a religious bigot.”

Sanders took equal aim at what he described as “the corrupt political system in which billionaires buy elections,” and then called out primary rival Mike Bloomberg, the former New York mayor who has already poured more than $300 million into his own campaign.

His campaign, he said, was as much about taking on “the greed and corruption” of Wall Street and corporate America as is was about denying Trump a second term.

“We’re going to win this election because we have an agenda that speaks to the needs of working people,” Sanders said.

After taking a swing at the Democratic establishment, Sanders said he would enact a wish list of progressive policies, including guaranteed health care, an ambitious response to climate change, free tuition at public post-secondary institutions and criminal justice and immigration reform.

“If we can bail out the crooks on Wall Street and give tax breaks to billionaires, we can cancel all student debt,” he said, drawing the loudest cheers of the rally from the mostly young crowd.

It was the second rally Sanders has held in Colorado since declaring his 2020 candidacy. In September, he called on 10,000 people at Denver’s Civic Center to “wage a political revolution,” vowing to raise the minimum wage and enact Medicare for All and the Green New Deal if elected president.

Sanders was introduced Sunday by former state Rep. Joe Salazar, one of the first Colorado politicians to endorse Sanders in 2016 and the director of an anti-fracking organization.

Salazar blasted “incrementalist, moderate cowards” and said that billionaires and oligarchs were trying to buy the election, and the crowd booed in support.

“Bernie is the only candidate that we have that is honest, has integrity and that you can trust,” Pilar Chapa, the campaign’s state director and a former executive director of the Colorado Democratic Party, told the crowd, and then added: “I have a message for you from Bernie. He trusts you!”

Sporting half a dozen Bernie buttons and holding a lit cigarette between her orange fingernails, Kim Heslin said outside the convention center that she was sold on Sanders.

“He’s trying to push for single payer and that’s something I believe in very much,” said the Colorado native from Aurora. She’s a medical biller and sees the “outrageous crisis” that most of the public is not aware of.

“You know somebody got sick. It’s not like they went and racked up a credit card.”

Heslin said she’s confident Sanders will win the Democratic nomination – but if he doesn’t, come November, she’ll be writing him in on the ballot.

“Honestly, I don’t see myself voting for any of these corporate Democrats or Trump. Definitely not.”

Alex Maldonado said he was “trepidatiously excited” to attend his first political rally, although he isn’t a strong Bernie supporter and was leaning toward Warren.

Maldonado said the primaries are about people getting to know the candidates, but also about the party getting to know what its base values.

As an example, Maldonado said, Biden, the Democrats’ establishment candidate, wouldn’t even have mentioned Medicare for All four years ago.

“It’s also about moving the needle forward,” he said.

Polling in the state has been scarce, but an August survey of likely primary voters found Sanders, Biden and Massachusetts Sen. Elizabeth Warren bunched at the top. That was months before Bloomberg entered the race and began pouring millions of dollars into advertising, and established an extensive field organization to chase ballots.

Since voting began earlier this month, two centrist Democrats have emerged as contenders in Colorado after strong showings in Iowa and New Hampshire: Minnesota Amy Klobuchar and former South Bend, Indiana, Mayor Pete Buttigieg, who holds the lead in delegates.

Presidential candidates are swarming Colorado as voters start to return ballots, which went in the mail to voters last week and are due to election officials by March 3.

Bloomberg visited a campaign office in Denver on Feb. 1, and Biden is attending a private fundraiser in Denver on Monday. Buttigieg plans to hold a town hall in Aurora on Saturday, and Warren  is holding a town hall in Denver on Feb. 23.

Trump, who doesn’t face significant opposition in the Republican primary, plans to hold a rally on Thursday in Colorado Springs with U.S. Sen. Cory Gardner.

National Republicans ripped Sanders’ “extreme socialist agenda” in a statement to Colorado Politics.

“Coloradans already made it loud and clear they have zero interest in Bernie Sanders’ government takeover of health care,” said Kyle Kohli, the Republican National Committee spokesman for Colorado. “Sanders’ extreme socialist agenda doesn’t stand a chance in a state like Colorado where voters constantly opposed statewide tax increases.”

Rachel Lorenz contributed to this report.